#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H

// 获取结构体成员偏移量
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

// 通过成员指针获取包含它的结构体指针
#define container_of(ptr, type, member) ({ \
    const typeof(((type *)0)->member) *__mptr = (ptr); \
    (type *)((char *)__mptr - offsetof(type, member)); })

// 双向链表基础结构
struct list_head {
    struct list_head *next, *prev;
};

// 初始化链表头
#define LIST_HEAD_INIT(name) { &(name), &(name) }

// 声明并初始化链表头
#define LIST_HEAD(name) \
    struct list_head name = LIST_HEAD_INIT(name)

// 运行时初始化链表
static inline void INIT_LIST_HEAD(struct list_head *list)
{
    list->next = list;
    list->prev = list;
}

// 内部链表插入函数
static inline void __list_add(struct list_head *new,
                  struct list_head *prev,
                  struct list_head *next)
{
    next->prev = new;
    new->next = next;
    new->prev = prev;
    prev->next = new;
}

// 在指定节点后添加新节点
static inline void list_add(struct list_head *new, struct list_head *head)
{
    __list_add(new, head, head->next);
}

// 在指定节点前添加新节点
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
    __list_add(new, head->prev, head);
}

// 内部链表删除函数
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
    next->prev = prev;
    prev->next = next;
}

// 删除链表节点
static inline void list_del(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    entry->next = (struct list_head *)0xDEADBEEF;
    entry->prev = (struct list_head *)0xDEADBEEF;
}

// 检查链表是否为空
static inline int list_empty(const struct list_head *head)
{
    return head->next == head;
}

// 遍历链表
#define list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)

// 安全遍历链表（允许删除节点）
#define list_for_each_safe(pos, n, head) \
    for (pos = (head)->next, n = pos->next; pos != (head); \
        pos = n, n = pos->next)

// 获取链表节点所在的结构体
#define list_entry(ptr, type, member) \
    container_of(ptr, type, member)

// 遍历链表并获取包含链表的结构体
#define list_for_each_entry(pos, head, member) \
    for (pos = list_entry((head)->next, typeof(*pos), member); \
         &pos->member != (head); \
         pos = list_entry(pos->member.next, typeof(*pos), member))

// 安全遍历链表并获取包含链表的结构体
#define list_for_each_entry_safe(pos, n, head, member) \
    for (pos = list_entry((head)->next, typeof(*pos), member), \
         n = list_entry(pos->member.next, typeof(*pos), member); \
         &pos->member != (head); \
         pos = n, n = list_entry(n->member.next, typeof(*n), member))

#endif /* _LINUX_LIST_H */
